Casing perforator



1934- .1. H. SLOCUM El AL CAS ING PERFORATOR Filed Jan. 25, 1933 Patented Feb. 6, 1934 UNITED STATES CASING PERFORATOR Joseph H. Slocum, Long Beach, and Bert L. Welch, Fullerton, Calif.; said Welch assignor to said Slocum Application January 25, 1933. Serial No. 653,400

Claims.

This invention relates to a casing perforator, such as employed for perforating well casings. The general object of the invention is to produce a casing perforator of simple construction 5 in which perforating tools are employed, that are mounted in such a way that when they are actuated to engage the casing, they will exert a thrust upon the body of the perforator tool, that is substantially balanced. In many perforators 1 now in use, the thrust of the perforator tool forces the body of the perforator over against the wall of the casing opposite the perforated point and offers great resistance to the movement of the part of the tool that causes the perforating operation. Our invention avoids this objection.

A further object of the invention is to provide a tool of this kind including a yielding anchoring device which is connected with the perforator tool in such a way that the anchoring device will be advanced down the casing ahead of the body of the perforator and so connected to the perforator that by an upward movement of the perforator relative to the mandrel and anchoring device the anchoring device can be released sufficiently to permit relative movement of a spear and slips, thereby enabling the spear to jam the slips in the casing before the force is exerted to effect the actual perforating operation.

A further object of the invention is to provide a tool of this type which can readily be moved up a slight distance after each perforating operation to enable a series of perforations to be formed in the casing.

A further object of the invention is to provide a construction for a perforator which will enable relatively long perforator tools to be employed and to mount the same so that a relatively great force can be exerted upon the tools to enable them to perforate two or more strings of easing simultaneously.

Further objects of the invention will appear hereinafter.

The invention consists in the novel parts and combinations of parts to be described hereinafter, all of which contribute to produce an efficient casing perforator.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawing: I

Figure 1 is a side elevation of a perforator embodying our invention, certain parts being broken away and illustrating portions of the casing in longitudinal section.

Figure 2 is a view similar to Figure 1 but projected onto a plane substantially at right angles to the plane of Figure 1. This figure and Figure 60, 1 show the perforator with the relation that the parts have when it is passing down the casing.

Figure 3 is a vertical section taken through the perforator in the same plane as Figure 2 and illustrating the relation of the parts after the perforator has been operated to drive the per-, forator tools through two strings of casing which are illustrated in longitudinal section. This view shows the latching means in its released position.

Figure 4 is a side elevation of the partsshown in Figure 3 as viewed from the left side, that is to say, this view shows the parts in the relation they have after a perforating operation has taken place.

Referring more particularly to the parts, 1 indicates the upper head of the perforator which is formed with means such as a pin 2 at its'upper end for securing the same to the lower end of a tool string. Below the head 1, we provide a sprear 3 which is supported on the head 1 by suitable suspending means preferably consisting of two long bolts or rods 4 that extend downwardly through guide openings 5 at diametrically opposite points in the spear, the lower ends of the bolts being provided with nuts 6 upon which the lower end of the spear may rest.

The spear includes a downwardly tapered body portion 7 and is formed with diametrically oppo- 7 site chambers 8 to facilitate carrying slips 9 which are preferably two in number and disposed diametrically opposite to each other. The lower end of the spear is in the form of a collar 10 through which a mandrel 11 passes upwardly, the upper end of the mandrel being received in a guide bore 12 located centrally in the body portion of the spear. The lower end of the mandrel carries a yielding gripping device 13 which may be of the cage type, including a plurality of jaw springs 14 which frictionally engage the wall of the casing 15.

We provide perforating tools 16 which are preferably relatively long and which are pivotally attached on pins 17 at two diametrically opposite points at the lower end of the head 1. These tools incline in opposite directions and cross each other to enable the tool that is pivoted at the right to have its point penetrate the opposite wall of the casing, and vice versa. These tools 16 cross each other like a pair of scissors, and at the crossing point they are provided with perforations 18 which register together to receive a frangible pin 19. The lower ends of the perforator tool 16 are received in notches 20 formed on the upper end of the spear and at diametrically opposite points. These notches have inclined bottom faces 21 to engage the inside edges of the 7 tools at their lower ends.

Associated with the mandrel 11 and the collar 10 we provide latching means to enable the descending spear to push the mandrel 11 and gripping device 13 down the casing. This latching means preferably consists of a latch or dog '22 (see Figure 3) which is pivotally mounted on a pin 23 in a recess 24 in the side of the mandrel. When the perforator is being run down the casing, this latch 22 is in an inclined position as illustrated in Figure 2, to engage the bottom of a notch 25 in the lower face of the collar. However, when the perforator has arrived at the depth where itis desired to make the perforations, an upward pull on the head 1 will cause the collar 10 to move upwardly and release the latch, whereupon a coil spring 26 in the bottom of the recess 24 will pull the latch into the mandrel. This will permit a relative downward movement of the spear on the mandrel.

This relative downward movement will set or jam the slips 9 against the wall of the casing, for example, an inner casing 27 (see Figure 3) The slips 9 are movably attached to the mandrel at a point between the collar 10 and the tapered body portion '7. For this purpose we prefer to provide the mandrel with a slot in which a short crosshead 28 is secured, the ends of the orosshead being connected to the lower ends of the slips by short links 29 that may incline outwardly in'an upward direction.

This perforator can be readily used for forming a series of perforations 30 (see Figure 3) I in a casing, or through two casing walls 27 and 31. In order to do this, the lowest perforations would be formed first, then by pulling up on the tool string carrying the head 1, the gripping device 13 can be pulled upto a higher level; then by lowering the head 1, the spear 3 will immediately jam the slips 9 and then by giving another down jar to the head, the tools 16 can be forced through the casing at a higher level. In this way by repeated operations the series of perforations can be put in the casing.

The general mode of operation of the perforator will now be described, The perforator is passed'down into the well with the parts in the relationindicated' in Figures 1' and 2. In doing this the collar 10 at the lower end of the spear exerts a thrust on the latch 22, and this pushes the mandrel 11 and the gripping device 13 down the casing. After the perforator has been put down to the desired depth, the head 1 is pulled upwardly, thereby releasing the latch 22 and enabling its spring 26 to pull it into the recess 24 in the side of the mandrel. In this position the latch will permit the collar 10 to pass downwardly, and as this collar is part of the spear,

the tapered body portion 7 of the spear will set the slips 9 against the casing. A down jar on the head 1 will then break the frangible member 19 and cause the perforator tool 16 to cam outwardly on the inclined faces 21 at the bottoms of the notches 20, and drive them through the wall of the casing. It will be noted that the thrust of each of these tools on the head 1 is opposite in direction to the thrust exerted by the other tool; therefore these thrusts balance each 1 other and there isno tendency to throw the head 1 over against the wall or" the casing, which would increase the resistance to a down jar and thereby interfere with the efficiency of the tool. In this way all the force of the down jar is exerted to cause penetration of the perforator tools.

What we claim is:

- 1. In a casing perforator, the combination of an upper head, a pair of perforator tools pivotally attached. to the head at diametrically opposite points and mounted so that they cross each other in an inclined position, a spear, means for sus' pending the spear from the head, a mandrel having an anchoring at its lower end extending up through the spear, means for holding the spear in a relatively elevated position on the mandrel in passing the perforator down the casing and operating to release the spear for downward movement on the mandrel when the spear is pulled upwardly on th mandrel, slips carried by the mandrel to co-operate with the spear to jam the same on the casing, thereby enabling downward movement of the upper head thereafter to force the perforator tools through the casing.

2. In a casing perforator, the combination 1 of an upper head, a pair of perforating tools pivotally mounted respectively on opposite sides of the head so that they cross each other in an inclined position, a spear, means for suspending the spear from the head, said means permitting 165 to the mandrel, latching means including a latch n5 for engaging the collar to hold the spear in a relatively elevated position on the mandrel, said latching means having means for releasing the latch when the spear is pulled upwardly on the mandrel, and operating thereafter to permit a downward movement of the spear on the mandrel to jam the slips, said spear cooperating with the head when the same is moved downwardly thereafter to force the tools through the wall of the casing. 1

3. In a casing perforator, the combination of a yielding anchoring means for engaging the wall of the casing to be perforated, a mandrel attached to the anchoring means and extending upwardly therefrom, slips, means for movably supporting the slips on the mandrel, a spear having a tapered body for engaging the slips to jam the same in the casing, latching means cooperating with the mandrel and the spear for holding the spear relatively elevated with respect to the slips when the 1 perforator is moving down the casing, said latching means operating to release the spear upon a relative upward movement of the spear with respect to the mandrel to permit a downward movement of the spear thereafter, a head above 1 the spear, rods connecting the head with the spear and permitting a relative downward movement of the head on the spear, and a pair of oppositely disposed perforator tools mounted in an inclined position, extending downwardly from 1 the head and resting on the upper end of the spear, said spear operating to exert a cam action on the tools when the spear has jammed the slips, to force the perforating tools outwardly and perforate the casing. 1

4. In a casing perforator, the combination of an upper head having means at its upper end for attaching the same to a tool string, a spear below the head, means for suspending the spear from the head and permitting relative upward movemen of the spear with respect to the head, a pair of oppositely disposed perforator tools pivoted to the lower end of the head and mounted in a cross relation, a frangible member connecting the perforator tools, the lower ends of said tools resting on the upper end of the spear, a mandrel extending up through the lower end of the spear, gripping means carried by the lower end of the mandrel for engaging the casing to hold the mandrel yieldingly in the casing, said spear having a tapered body portion and having a collar disposed therebelow for sliding on the mandrel, slips disposed above the collar to cooperate with the tapered portion of the spear, means for movably connecting the slips with the mandrel between the collar and the tapered portion of the spear, a latch carried on the mandrel for engaging the lower end of the collar to prevent downward movement of the spear relative to the slips when the perforator is passing down the well, said mandrel having a recess to receive the latch to permit the collar to pass downwardly, and a spring cooperating with the latch to move the latch into the recess when the collar is pulled upwardly relatively to the mandrel, thereby permitting a downward movement of the spear to jam the slips against the casing wall, the further downward movement of the head operating thereafter to fracture the frangible member and cause the perforating tools to move downwardly, the upper end of said spear exerting a cam action on the tools to force them through the casing.

5. In a casing perforator, the combination of an upper head, a pair of perforator tools pivotally attached to the lower end of the head at opposite points, said tools being disposed in a crossed relation and inclining downwardly, a pair of guide rods attached to the lower end of the head on opposite sides of the perforator tools, a spear supported on said guide rods and engaging the lower ends of the perforator tools, a gripping device on the mandrel for engaging the casing, said mandrel extending up through the lower end of the spear, a latching device associated with the mandrel for engaging the lower end of the spear to enable the spear to force the gripping device and mandrel down the casing, a pair of slips to cooperate with the spear, said latching device operating upon an upward movement of the spear on the mandrel, to releasev the spear and enable the same to cooperate with the slips to jam them on the casing, thereby enabling a further downward movement of the upper head to force the tools outwardly and perforate the casing.

JOSEPH H. SLOCUM. BERT L, WELCH. 

